package hashx

import (
	"crypto/md5"
	"crypto/sha1"
	"crypto/sha256"
	"crypto/sha512"
	"encoding/binary"
	"encoding/hex"
	"errors"
	"hash"
	"hash/crc32"
	"io"
	"os"

	gmsm3 "github.com/emmansun/gmsm/sm3"
	"golang.org/x/crypto/md4"
	"golang.org/x/crypto/ripemd160"
)

var (
	// ErrUnsupportedMethod reports an unknown hash method string.
	ErrUnsupportedMethod = errors.New("unsupported hash method")
)

func HexString(b []byte) string {
	return hex.EncodeToString(b)
}

func Md5(b []byte) []byte {
	sum := md5.New()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

func Md5Str(b []byte) string {
	return HexString(Md5(b))
}

func Md4(b []byte) []byte {
	sum := md4.New()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

func Md4Str(b []byte) string {
	return HexString(Md4(b))
}

func Sha512(b []byte) []byte {
	sum := sha512.New()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

func Sha512Str(b []byte) string {
	return HexString(Sha512(b))
}

func Sha384(b []byte) []byte {
	sum := sha512.New384()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

func Sha384Str(b []byte) string {
	return HexString(Sha384(b))
}

func Sha256(b []byte) []byte {
	sum := sha256.New()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

func Sha256Str(b []byte) string {
	return HexString(Sha256(b))
}

func Sha224(b []byte) []byte {
	sum := sha256.New224()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

func Sha224Str(b []byte) string {
	return HexString(Sha224(b))
}

func Sha1(b []byte) []byte {
	sum := sha1.New()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

func Sha1Str(b []byte) string {
	return HexString(Sha1(b))
}

func RipeMd160(b []byte) []byte {
	sum := ripemd160.New()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

func RipeMd160Str(b []byte) string {
	return HexString(RipeMd160(b))
}

func SM3(b []byte) []byte {
	sum := gmsm3.New()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

func SM3Str(b []byte) string {
	return HexString(SM3(b))
}

// CheckCRC32A returns CRC32A as uint32 in big-endian view.
// CRC32A here is an MSB-first, non-reflected variant and is different
// from Go standard library CRC-32/IEEE.
func CheckCRC32A(data []byte) uint32 {
	b := crc32aDigest(data)
	return binary.BigEndian.Uint32(b)
}

func Crc32Str(b []byte) string {
	return HexString(Crc32(b))
}

func Crc32(b []byte) []byte {
	sum := crc32.NewIEEE()
	_, _ = sum.Write(b)
	return sum.Sum(nil)
}

// Crc32A computes CRC32A (MSB-first, non-reflected), which is not the
// same route as Go standard library CRC-32/IEEE.
func Crc32A(data []byte) []byte {
	return crc32aDigest(data)
}

// Crc32AStr returns hex string of Crc32A digest.
func Crc32AStr(data []byte) string {
	return hex.EncodeToString(crc32aDigest(data))
}

func SumAll(data []byte, methods []string) (map[string][]byte, error) {
	if len(methods) == 0 {
		methods = []string{"sha512", "sha256", "sha384", "sha224", "sha1", "crc32", "md5"}
	}

	result := make(map[string][]byte, len(methods))
	hashers := make(map[string]hash.Hash, len(methods))
	var crc hash.Hash32

	for _, method := range methods {
		switch method {
		case "md5":
			hashers[method] = md5.New()
		case "sha1":
			hashers[method] = sha1.New()
		case "sha224":
			hashers[method] = sha256.New224()
		case "sha256":
			hashers[method] = sha256.New()
		case "sha384":
			hashers[method] = sha512.New384()
		case "sha512":
			hashers[method] = sha512.New()
		case "crc32":
			if crc == nil {
				crc = crc32.NewIEEE()
			}
		default:
			// Keep compatibility with previous behavior: unknown methods are ignored.
		}
	}

	for _, h := range hashers {
		_, _ = h.Write(data)
	}
	if crc != nil {
		_, _ = crc.Write(data)
	}

	for method, h := range hashers {
		result[method] = h.Sum(nil)
	}
	if crc != nil {
		result["crc32"] = crc.Sum(nil)
	}
	return result, nil
}

func FileSum(filePath, method string, progress func(float64)) (string, error) {
	fp, err := os.Open(filePath)
	if err != nil {
		return "", err
	}
	defer fp.Close()

	stat, err := fp.Stat()
	if err != nil {
		return "", err
	}

	var (
		h     hash.Hash
		h32   hash.Hash32
		is32  bool
		total int64
		size  = stat.Size()
	)

	switch method {
	case "sha512":
		h = sha512.New()
	case "sha384":
		h = sha512.New384()
	case "sha256":
		h = sha256.New()
	case "sha224":
		h = sha256.New224()
	case "sha1":
		h = sha1.New()
	case "md5":
		h = md5.New()
	case "crc32":
		h32 = crc32.NewIEEE()
		is32 = true
	default:
		return "", errors.New(ErrUnsupportedMethod.Error() + ": " + method)
	}

	buf := make([]byte, 1024*1024)
	for {
		n, readErr := fp.Read(buf)
		if n > 0 {
			total += int64(n)
			if is32 {
				_, _ = h32.Write(buf[:n])
			} else {
				_, _ = h.Write(buf[:n])
			}
			reportProgress(progress, total, size)
		}
		if readErr != nil {
			if readErr == io.EOF {
				break
			}
			return "", readErr
		}
	}

	if is32 {
		return hex.EncodeToString(h32.Sum(nil)), nil
	}
	return hex.EncodeToString(h.Sum(nil)), nil
}

func FileSumAll(filePath string, methods []string, progress func(float64)) (map[string]string, error) {
	if len(methods) == 0 {
		methods = []string{"sha512", "sha256", "sha384", "sha224", "sha1", "crc32", "md5"}
	}

	fp, err := os.Open(filePath)
	if err != nil {
		return nil, err
	}
	defer fp.Close()

	stat, err := fp.Stat()
	if err != nil {
		return nil, err
	}

	hashers := make(map[string]hash.Hash, len(methods))
	var crc hash.Hash32
	for _, method := range methods {
		switch method {
		case "md5":
			hashers[method] = md5.New()
		case "sha1":
			hashers[method] = sha1.New()
		case "sha224":
			hashers[method] = sha256.New224()
		case "sha256":
			hashers[method] = sha256.New()
		case "sha384":
			hashers[method] = sha512.New384()
		case "sha512":
			hashers[method] = sha512.New()
		case "crc32":
			if crc == nil {
				crc = crc32.NewIEEE()
			}
		default:
			// Keep compatibility with previous behavior: unknown methods are ignored.
		}
	}

	var total int64
	size := stat.Size()
	buf := make([]byte, 1024*1024)
	for {
		n, readErr := fp.Read(buf)
		if n > 0 {
			total += int64(n)
			chunk := buf[:n]
			for _, h := range hashers {
				_, _ = h.Write(chunk)
			}
			if crc != nil {
				_, _ = crc.Write(chunk)
			}
			reportProgress(progress, total, size)
		}

		if readErr != nil {
			if readErr == io.EOF {
				break
			}
			return nil, readErr
		}
	}

	result := make(map[string]string, len(hashers)+1)
	for method, h := range hashers {
		result[method] = hex.EncodeToString(h.Sum(nil))
	}
	if crc != nil {
		result["crc32"] = hex.EncodeToString(crc.Sum(nil))
	}
	return result, nil
}

func reportProgress(progress func(float64), current, total int64) {
	if progress == nil {
		return
	}
	if total <= 0 {
		progress(100)
		return
	}
	progress(float64(current) / float64(total) * 100)
}

func crc32aDigest(data []byte) []byte {
	var crc uint32
	digest := make([]byte, 4)

	crc = ^crc
	for i := 0; i < len(data); i++ {
		crc = (crc << 8) ^ crc32aTable[(crc>>24)^(uint32(data[i])&0xff)]
	}
	crc = ^crc

	digest[3] = byte((crc >> 24) & 0xff)
	digest[2] = byte((crc >> 16) & 0xff)
	digest[1] = byte((crc >> 8) & 0xff)
	digest[0] = byte(crc & 0xff)
	return digest
}

var crc32aTable = [256]uint32{
	0x0,
	0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
	0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6,
	0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
	0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac,
	0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f,
	0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a,
	0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
	0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58,
	0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033,
	0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe,
	0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
	0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4,
	0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
	0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5,
	0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
	0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07,
	0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c,
	0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1,
	0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
	0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b,
	0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698,
	0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d,
	0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
	0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f,
	0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
	0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80,
	0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
	0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a,
	0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629,
	0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c,
	0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
	0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e,
	0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65,
	0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8,
	0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
	0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2,
	0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
	0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74,
	0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
	0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21,
	0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a,
	0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087,
	0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
	0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d,
	0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce,
	0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb,
	0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
	0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09,
	0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
	0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf,
	0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4,
}